This study investigated the gastric acid resistance ofLactobacillus caseiin commercial fermented milks during refrigerated storage. Samples of fermented milks (natural, strawberry, fruits of the forest, vanilla and multifruits) were obtained from three different manufacturers. In vitro gastric acid resistance (GAR) was assessed in samples upon arrival to the laboratory and after 10 and 20 days of refrigerated storage at 5 °C and 12 °C. The GAR ofL. caseiin fermented milks may increase or decrease during storage in relation to the flavour and storage conditions. The occurrence of this phenomenon in commercial fermented milks containing probiotic bacteria may induce changes in their functionality after consumption.

The increase in vegetarianism as dietary habit and the increased allergy episodes against dairy proteins fuel the demand for probiotics in nondairy products. Lactose intolerance and the cholesterol content of dairy products can also be considered two additional reasons why some consumers are looking for probiotics in other foods. We aimed at determining cell viability in nondairy drinks and resistance to simulated gastric digestion of commercial probiotic lactobacilli commonly used in dairy products. Lactobacillus casei LC-01 and L. casei BGP 93 were added to different commercial nondairy drinks and viability and resistance to simulated gastric digestion (pH 2.5, 90 min, 37 °C) were monitored along storage (5 and 20 °C). For both strains, at least one nondairy drink was found to offer cell counts around 7 log orders until the end of the storage period. Changes in resistance to simulated gastric digestion were observed as well. Commercial probiotic cultures of L. casei can be added to commercial fruit juices after a carefull selection of the product that warrants cell viability. The resistance to simulated gastric digestion is an easy-to-apply in vitro tool that may contribute to product characterization and may help in the choice of the food matrix when no changes in cell viability are observed along storage. Sensorial evaluation is mandatory before marketing since the product type and storage conditions might influence the sensorial properties of the product due to the possibility of growth and lactic acid production by probiotic bacteria.

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El estudio tuvo como objetivo evaluar la digestibilidad de los nutrientes y energía digestible y metabolizable de la semilla y torta de sacha inchi (Plukenetia volubilis L) precocida y procesada (peletizado y extruido) en cuyes. En cada ensayo se utilizaron 15 cuyes machos, de 3 meses edad y peso promedio de 700 g. El peletizado se realizó a 87 °C y la extrusión a 105 °C. La digestibilidad y metabolicidad fue determinada utilizando el método de sustitución y colección total de excretas (heces y orina). Los valores de digestibilidad aparente (%) para materia seca, proteína bruta, fibra cruda y extracto etéreo para la semilla peletizada fueron de 54.4, 79.6, 27.0, 76.1 y semilla extruida de 48.7, 83.5, 16.2 y 81.7 respectivamente; mientras que para torta peletizada fueron de 82.5, 81.2, 98.7, 65.9 y torta extruida 76.7, 83.2, 92.8 y 62.4. La energía digestible en la semilla peletizada y extruida fue de 3296 y 3681 kcal/kg de materia seca, y en la torta peletizada y extruida fue de 4621 y 4161 kcal/kg de materia seca, respectivamente. La energía metabolizable en la semilla peletizada y extruida fue de 2676 y 3243 kcal/kg de materia seca, y en la torta peletizada y extruida fue de 4346 y 4137 kcal/kg de materia seca, respectivamente. El tipo de procesamiento no afectó los valores energéticos en la semilla y torta de sacha inchi.